Rio Rewilding Brings Extinct Animals Back After 200 Years

For 200 years, blue-and-yellow macaws were just a memory in Rio de Janeiro, but this January, their bright wings returned to the city's skies. They're the latest success in an ambitious mission to save Tijuca National Park from becoming what scientists call an "empty forest."

Empty forests look lush and green, but they're missing something crucial. Without animals to spread seeds, the trees can't reproduce, and the ecosystem slowly dies from the inside out.

Biologist Alexandra Pires discovered this firsthand in 2008 when she visited Tijuca and found thousands of seeds rotting on the ground. The agoutis that normally ate and dispersed these seeds had disappeared completely. "How can there be no agoutis in Tijuca National Park?" she remembers thinking.

That conversation launched Refauna, a rewilding program that's been bringing extinct species back to the forest for nearly two decades. Today, over 60 red-rumped agoutis live in the park, including fourth-generation descendants of the first ones released in 2009.

The project's ambitions stretch back even further. In 1861, Brazil's emperor ordered the devastated mountains outside Rio replanted after coffee plantations destroyed the original forest. Thousands of native trees were planted, but without animals, the restored forest couldn't sustain itself.

The first animal comeback happened in 1970 when researchers released 46 channel-billed toucans. A study published just this year proved those birds succeeded beyond expectations, interacting with 76% of their original food plants and spreading seeds of threatened species like the juçara palm.

Brown howler monkeys returned in 2015 after vanishing for more than a century. Their powerful calls now echo through the forest again, and they're dispersing large seeds that few other animals can carry.

The Ripple Effect

The animals aren't just returning—they're actively rebuilding the forest's future. Toucans crack open hard seeds with their powerful beaks, reaching species other birds can't touch. Agoutis bury seeds across the forest floor, essentially planting new trees. Yellow-footed tortoises carry seeds to new locations as they wander.

Each species plays a unique role that can't be replaced. In the Atlantic Forest, nine out of every 10 plant species depend on animals to spread their seeds.

The work takes patience and careful planning. Scientists must verify that Tijuca can support each species with enough food and shelter before any release happens. They need healthy animals in sufficient numbers, because releasing too few means the population likely won't survive.

After selection comes months of acclimatization in forest enclosures, then monitoring after release. The macaws proved this necessity when they had to be recaptured and retrained before successfully adapting to their new home.

Visitors to Tijuca can now witness what was nearly lost forever: a forest alive with the rustling, calling, and flying of creatures that belong there. Each returned species brings the ecosystem one step closer to the thriving forest it once was.